In the first part of this chapter, you familiarized yourself with
QNetworkAccessManager. This class is at the heart of your code whenever you want to download or upload files to the Internet. After having gone through the different signals that you can use to fetch errors, to get notified about new data or to show the progress, you should now know everything you need on that topic.
The example about the Distance Matrix API depended your knowledge of
QNetworkAccessManager, and it shows you a real-life application case for it. Dealing with JSON as the server's reply format was a recapitulation of Chapter 4, Qt Core Essentials, but was highly needed since Facebook or Twitter only use JSON to format their network replies.
In the last section, you learned how to set up your own TCP server and clients. This enables you to connect different instances of a game to provide the multiplayer functionality. Alternatively, you were taught how to use UDP.
Please keep in mind that we only scratched...